Abstract: An emulation system is constituted with a plurality of FPGAs having on-chip integrated debugging facilities, distributively disposed on a plurality of circuit boards. Each FPGA's on-chip integrated debugging facilities include in particular, a scan register for outputting trace data, and comparison circuitry for generating inputs for a plurality of system triggers. Correspondingly, each board is provided with a plurality of trace memory for recording the trace data, and summing circuitry for generating partial sums for the triggers. The relative memory location within a clock cycle of trace data where the output of a LE will be recorded is predeterminable. Additionally, a system sync memory is provided for storing a plurality of sync patterns to facilitate reconstitution of trace data of a trace session.

Abstract: A scalable multi-level multi-stage network topology is employed to interconnect reconfigurable logic elements within the FPGA, inter-FPGA, interlogic boards, and inter-backplanes. More specifically, under the presently preferred embodiemnt, an on-chip 3-stage inter-logic element crossbar network is provided to each FPGA for interconnecting the reconfigurable logic elements and the I/O pins of the FPGA. A two level two-stage inter-FPGA crossbard network is provided to interconnect the FPGAs and I/O pins of the logic board. A two-level two-stage inter-board crossbar network is provided to interconnect the logic boards or I/O boards for interconnecting the logic elements to external devices. Finally, a single-stage inter-backplane network and a number of PCBs are provided to interconnect multi-backplanes to form a multi-crate system.